Electronic engine immobilizer systems for vehicles are known. An electronic engine control module, or security module which operates with the electronic engine control module, is generally in an armed state whenever the engine is switched off. This prevents the engine from being started (for example, by disabling the spark distribution system and/or the fuel injection system). The immobilizer system may be disarmed by use of the correct electronic vehicle key. Typically, a radio frequency (RF) transceiver is located in the head of a conventional mechanical key for the standard mechanical lock on the steering column of the vehicle. The transponder has a unique digital security code. The code is sent to an RF transceiver in the vehicle and the security code is passed to the security module or electronic engine control module of the vehicle. If the security code matches a security code stored in the security module or electronic engine control module, the engine immobilizer function is disarmed. Once the engine is switched off again, the security module or electronic engine control module is returned to an armed state.
Electronic vehicle access systems are known. Typically, an electronic vehicle access control module or security module is connected to the central locking system of the vehicle, for securing all vehicle access points, and to a RF receiver located in the vehicle such that RF signals may be received from inside and outside the vehicle. An RF transmitter is located in the head of a conventional mechanical key, or in a separate electronic key device, and is operable, by activation of a push button, to transmit a unique digital security code which may be received by the RF receiver of the vehicle and passed to the electronic vehicle access control module or security module. If the security code matches a security code stored in the electronic vehicle access control module or security module, the central locking system of the vehicle is controlled to toggle between a locked and an unlocked state. The RF transmitter is typically sufficiently powerful to transmit a receivable signal over a distance of a few metres. Thus, access points to a vehicle may be locked or unlocked remotely.
U.S. Pat. No. 6,181,026 describes a vehicle immobilizer system for electronic engine control in which the controller for the engine immobilizer, when in a disarmed state, monitors engine-running sensors and switches to the armed state if the engine-running sensors indicate that the engine is not running even though the ignition switch has not been detected have been put in the off position.
International patent publication WO 01/25572 describes a vehicle access system with an electronic key which provides an authorisation signal without requiring manual activation by the user. The system includes two modes, one of which is a conventional mode and the other of which is referred to as a valet mode. Vehicle functions, such as unlocking of the car boot, are prevented in valet mode of operation. The valet mode does not prevent vehicle theft by a person having use of the electronic key, since a valet is required to be able to drive the vehicle on behalf of the owner.
GB-A-2305216 discloses a security controller for a vehicle which receives “lock” and “unlock” signals from a portable transmitter unit. If the vehicle is stolen and correct authorisation given, a remote station will transmit a “disable” signal which will cause the controller to disable the vehicle. The security controller can allow the remote station to track the vehicle. The remote station can transmit signals which override signals from the portable transmitter.
During the distribution of recently manufactured vehicles, it is common to place the vehicles in a secure mass storage area. To allow quick operation of the vehicles in the storage area, the vehicles may be left with the vehicle keys inside and the doors of the vehicles unlocked. However, control of access to the secure area is difficult to administer and vehicle theft can be a problem unless expensive security measures are implemented. Similar problems arise in other situations in which the vehicle keys are kept in the vicinity of the vehicle.
The present invention aims to provide a solution to such problems.